Porous gas bearing

ABSTRACT

A porous gas bearing is disclosed. The porous gas bearing includes a housing having a fluid inlet and an aperture. A porous surface layer is disposed within the housing surrounding the aperture in a circumferential direction. The porous surface layer is in fluid communication with the fluid inlet. A damping system includes a damping system including a biasing member, the biasing member being disposed in a passageway that extends along the longitudinal direction of the aperture and circumferentially about the aperture, wherein the biasing member is arranged radially outward from the porous surface layer.

FIELD

This description relates generally to a bearing for a heating,ventilation, air conditioning, and refrigeration (HVACR) system. Morespecifically, this description relates to a porous gas bearing for acompressor in the HVACR system.

BACKGROUND

A heating, ventilation, air conditioning, and refrigeration (HVACR)system generally includes a compressor. Compressors, such as, but notlimited to, centrifugal compressors, screw compressors, and scrollcompressors, utilize bearings to support a spinning shaft. Various typesof bearings have been considered, including hydrodynamic oil bearingsand ball bearings, which require a lubricant system. In somecircumstances, an oil-free operation is preferred. Such systems oftenutilize a magnetic bearing. Magnetic bearings do not utilize alubricant, but can be expensive and require a control system.

HVACR systems can be utilized for a building or may be utilized in atransport application (e.g., trucks, cars, buses, trains, etc.).

SUMMARY

This description relates generally to a bearing for a heating,ventilation, air conditioning, and refrigeration (HVACR) system. Morespecifically, this description relates to a porous gas bearing for acompressor in the HVACR system.

In an embodiment, a porous gas bearing is disclosed. The porous gasbearing can be used to, for example, support a shaft such as, but notlimited to, a compressor shaft of a compressor in an HVACR system. In anembodiment, the compressor can be a centrifugal compressor. In anembodiment, the centrifugal compressor is an oil-free centrifugalcompressor.

The porous gas bearing can include a damping feature. In an embodiment,the porous gas bearing can include a plurality of damping features. Thedamping feature can, for example, reduce an amount of radialdisplacement of a shaft in a compressor.

A porous gas bearing is disclosed. The porous gas bearing includes ahousing having a fluid inlet and an aperture. A porous surface layer isdisposed within the housing surrounding the aperture in acircumferential direction. The porous surface layer is in fluidcommunication with the fluid inlet. A damping system includes a biasingmember. The biasing member is disposed in a passageway that extendsalong the longitudinal direction of the aperture and circumferentiallyabout the aperture. The biasing member is arranged radially outward fromthe porous surface layer.

A refrigerant circuit is disclosed. The refrigerant circuit includes acompressor, a condenser, an expansion device, and an evaporator fluidlyconnected. The compressor includes a shaft. The shaft is supported by aporous gas bearing. The porous gas bearing includes a housing having afluid inlet and an aperture. A porous surface layer is disposed withinthe housing surrounding the aperture in a circumferential direction. Theporous surface layer is in fluid communication with the fluid inlet. Adamping system includes a biasing member. The biasing member being isdisposed in a passageway that extends along the longitudinal directionof the aperture and circumferentially about the aperture. The biasingmember is arranged radially outward from the porous surface layer.

A centrifugal compressor is disclosed. The centrifugal compressorincludes a shaft that rotates and a porous gas bearing. The porous gasbearing includes a housing having a fluid inlet and an aperture. Aporous surface layer is disposed within the housing surrounding theaperture in a circumferential direction. A porous surface layer isdisposed within the housing surrounding the aperture in acircumferential direction. The porous surface layer is in fluidcommunication with the fluid inlet. A damping system includes a biasingmember. The biasing member being is disposed in a passageway thatextends along the longitudinal direction of the aperture andcircumferentially about the aperture. The biasing member is arrangedradially outward from the porous surface layer.

BRIEF DESCRIPTION OF THE DRAWINGS

References are made to the accompanying drawings that form a part ofthis disclosure and which illustrate embodiments in which the systemsand methods described in this specification can be practiced.

FIG. 1 is a schematic diagram of a refrigeration circuit, according toan embodiment.

FIGS. 2A-2C are schematic views of a porous gas bearing having a dampingsystem, according to an embodiment.

FIGS. 3A and 3B are schematic views of a porous gas bearing having adamping system, according to an embodiment.

FIGS. 4A and 4B are schematic views of a porous gas bearing having adamping system, according to an embodiment.

FIGS. 5A-5D are schematic views of a porous gas bearing having a dampingsystem, according to an embodiment.

FIGS. 6A and 6B are schematic views of a porous gas bearing having adamping system, according to an embodiment.

FIG. 7 is a schematic view of a porous gas bearing having a dampingsystem, according to an embodiment.

FIGS. 8A and 8B are schematic views of a porous gas bearing having adamping system, according to an embodiment.

FIGS. 9A and 9B are schematic views of a porous gas bearing having adamping system, according to an embodiment.

Like reference numbers represent like parts throughout.

DETAILED DESCRIPTION

This description relates generally to a bearing for a heating,ventilation, air conditioning, and refrigeration (HVACR) system. Morespecifically, this description relates to a porous gas bearing for acompressor in the HVACR system.

A porous gas bearing, as used in this specification, generally includesa layer of porous material on a bearing surface that includes an evenlydistributed fluid flow over the porous surface. In an embodiment, thefluid flow can be a gas. In an embodiment, the fluid flow can be amixture of a gas and a liquid.

In an embodiment, the porous gas bearing can be utilized in place of ahydrodynamic oil bearing, a ball bearing, a magnetic bearing, or thelike. In particular, the porous gas bearing can be utilized in acompressor (e.g., a centrifugal compressor, etc.) of an HVACR system toprovide a lubricant free system. Typically, porous gas bearings mayprovide a limited amount of damping due to a relatively low viscosity ofthe working fluid. In the embodiments disclosed in this specification,various damping systems are disclosed that can address the limiteddamping of porous gas bearings. Additionally, embodiments disclosed inthis specification can include a porous gas bearing that utilizesrefrigerant as the working fluid, which can increase a viscosity of theworking fluid and can, for example, provide advantageous heat transferproperties to reduce a likelihood of bearing seizure due to thermalexpansion of a shaft supported by the porous gas bearing.

FIG. 1 is a schematic diagram of a refrigerant circuit 10, according toan embodiment. The refrigerant circuit 10 generally includes acompressor 12, a condenser 14, an expansion device 16, and an evaporator18.

The refrigerant circuit 10 is an example and can be modified to includeadditional components. For example, in an embodiment, the refrigerantcircuit 10 can include other components such as, but not limited to, aneconomizer heat exchanger, one or more flow control devices, a receivertank, a dryer, a suction-liquid heat exchanger, or the like.

The refrigerant circuit 10 can generally be applied in a variety ofsystems used to control an environmental condition (e.g., temperature,humidity, air quality, or the like) in a space (generally referred to asa conditioned space). Examples of such systems include, but are notlimited to, HVACR systems, transport refrigeration systems, or the like.

The compressor 12, condenser 14, expansion device 16, and evaporator 18are fluidly connected via refrigerant lines 20, 22, 24. In anembodiment, the refrigerant lines 20, 22, and 24 can alternatively bereferred to as the refrigerant conduits 20, 22, and 24, or the like.

In an embodiment, the refrigerant circuit 10 can be configured to be acooling system (e.g., an air conditioning system) capable of operatingin a cooling mode. In an embodiment, the refrigerant circuit 10 can beconfigured to be a heat pump system that can operate in both a coolingmode and a heating/defrost mode.

The refrigerant circuit 10 can operate according to generally knownprinciples. The refrigerant circuit 10 can be configured to heat or coola gaseous process fluid (e.g., a heat transfer medium or fluid such as,but not limited to, air or the like), in which case the refrigerantcircuit 10 may be generally representative of an air conditioner or heatpump.

In operation, the compressor 12 compresses a working fluid (e.g., a heattransfer fluid such as a refrigerant or the like) from a relativelylower pressure gas to a relatively higher-pressure gas. In anembodiment, the compressor 12 can be a centrifugal compressor. In anembodiment, the centrifugal compressor can operate at different speedranges based on, for example, the compressor size and type. For example,in an embodiment, the centrifugal compressor can operate from at orabout 10,000 revolutions per minute (RPM) to at or about 150,000revolutions per minute (RPM). In an embodiment, the compressor 12 can bea screw compressor, a scroll compressor, or the like.

The relatively higher-pressure gas is also at a relatively highertemperature, which is discharged from the compressor 12 and flowsthrough refrigerant line 20 to the condenser 14. The working fluid flowsthrough the condenser 10 and rejects heat to a process fluid (e.g.,water, air, etc.), thereby cooling the working fluid. The cooled workingfluid, which is now in a liquid form, flows to the expansion device 16via the refrigerant line 22. The expansion device 16 reduces thepressure of the working fluid. As a result, a portion of the workingfluid is converted to a gaseous form. The working fluid, which is now ina mixed liquid and gaseous form flows to the evaporator 18 via theremainder of refrigerant line 22. The working fluid flows through theevaporator 18 and absorbs heat from a process fluid (e.g., water, air,etc.), heating the working fluid, and converting it to a gaseous form.The gaseous working fluid then returns to the compressor 12 via therefrigerant line 24. The above-described process continues while therefrigerant circuit is operating, for example, in a cooling mode (e.g.,while the compressor 12 is enabled).

In the illustrated embodiment, a first fluid line 26 can be connected ata location at which fluid may be drawn from the compressor 12 andprovided to a porous gas bearing in the compressor 12. In an embodiment,fluid line 26 can be connected at a location at which fluid provided tothe porous gas bearing is gaseous or substantially gaseous. Embodimentsof porous gas bearings are discussed in additional detail in accordancewith FIGS. 2A-9B below. A second fluid line 28 can be connected at alocation at which fluid may be drawn from the refrigerant line 22 andprovided to the porous gas bearing. In an embodiment, fluid line 28 canbe connected at a location at which fluid provided to the porous gasbearing is in a mixed state including at least a portion that is liquidand at least a portion that is gaseous. It will be appreciated that thefirst fluid line 26 can be included in the refrigerant circuit 10, thesecond fluid line 28 can be included in the refrigerant circuit 10, orboth the first and second fluid lines 26, 28 can be included in therefrigerant circuit 10.

FIGS. 2A-2C are schematic views of a porous gas bearing 30 having adamping system, according to an embodiment. FIG. 2A is an axialcross-section of the porous gas bearing 30, according to an embodiment.FIG. 2B is a view of an inner surface of the porous gas bearing 30 ifunwound, according to an embodiment. FIG. 2C is an axial cross-sectionof the porous gas bearing 30 including modifications to the dampingsystem, according to an embodiment.

The porous gas bearing 30 in FIGS. 2A-2C can be utilized in a compressor(e.g., compressor 12 in FIG. 1) of a refrigerant circuit (e.g.,refrigerant circuit 10 in FIG. 1) of an HVACR system.

The porous gas bearing 30 with damping system includes a housing 34, aporous surface layer 36, and dampers 38 formed within the housing 34.

The porous surface layer 36 extends from a first end of the housing 34to a second end of the housing 34. In the illustrated embodiment, theporous surface layer 36 includes a plurality of segments 36A-36C. Eachsegment 36A-36C is spaced apart from another segment 36A-36C. Opposingends of the individual segments 36A and 36B are longitudinally spacedfrom each other. Opposing ends of the individual segments 36B and 36Care longitudinally spaced from each other. The segments are separated bya circumferential groove 50 in which the dampers 38 are formed. (SeeFIG. 2B). It will be appreciated that a number and size of the segments36A-36C can vary. The number and size of the segments 36A-36C can beselected to provide a selected amount of damping and a selectedstiffness for the porous gas bearing 30. The porous surface layer 36can, in an embodiment, be made of a porous carbon graphite material. Inan embodiment, the porous surface layer 36 can be any suitable porousmaterial to accomplish the functionality described in thisspecification. In an embodiment, a porosity of the material can varybased on application and operating conditions. In an embodiment, theporous surface layer 36 can have a porosity of at or about 10% to at orabout 30%.

The porous surface layer 36 is in fluid communication with a fluid inlet40. It will be appreciated that a number of fluid inlets 40 can be basedon a number of the segments 36A-36C of the porous surface layer 36. Thatis, in the illustrated embodiment, there are three fluid inlets 40A,40B, and 40C, which correspond to the porous surface layers 36A, 36B,36C. In an embodiment, there may be a single fluid inlet 40 that issplit to be provided to the porous surface layer 36. Such an embodimentis shown and described in accordance with FIG. 7 below.

A shaft 42 can be provided within an aperture 44 of the housing 34. Theshaft 42 includes a longitudinal axis L-L that extends along a length ofthe shaft 42. In an embodiment, a clearance between the shaft 42 and theporous surface layer 36 can be at or about 2 microns to at or about 100microns. A larger clearance means lower stiffness and larger leakagethrough the porous gas bearing 30. The selection of the clearance candepend, for example, upon the required stiffness of the rotor-bearingsystem. A radial direction R is shown in the figure. In operation, theshaft 42 rotates about the longitudinal axis L-L. The shaft 42 issubject to deflection in the radial direction R. To reduce an amount ofmovement in the radial direction R, the dampers 38 of the damping systemcan receive fluid F from the displacement of the shaft 42.

The dampers 38 include a damper inlet 46 and a damper chamber 48. Thedampers 38 are illustrated as being fluidly separate in FIG. 2A. It willbe appreciated that the dampers 38 can be fluidly connected. The damperinlet 46 and the damper chamber 48 can be sized (e.g., to a selectedvolume, etc.) to provide a selected amount of damping.

In an embodiment, the dampers 38 can be configured differently atdifferent locations along the longitudinal axis L-L of the shaft 42. Inan embodiment, this can, for example, provide selective damping atparticular locations of the shaft 42 that may be subject to more radialmovement than other locations of the shaft 42.

In an embodiment, the dampers 38 may be machined into the housing 34 viathe aperture 44. In an embodiment, it may be relatively simpler tomanufacture the dampers 38 by machining the housing 34 from a radialouter direction toward the aperture 44. In such an embodiment, thehousing 34 may be mechanically capped to prevent fluid from escaping thedampers 38. For example, with reference to FIG. 2C, a bolt 59 can beinserted into the damper chamber 48. In such an embodiment, a volume ofthe damper chamber 48 may be determined based on how far into the damperchamber 48 the bolt 59 is inserted.

With reference to FIG. 2B, the dampers 38 may be disposed in acircumferential groove 50 that is located between the segments 36A-36Cof the porous surface layer 36.

In operation, a fluid flow F is provided from a fluid source 52. Thefluid source 52 can include, for example, fluid diverted from arefrigerant circuit (e.g., the refrigerant circuit 10 in FIG. 1). In anembodiment, the fluid source 52 can be a source that is fluidly separatefrom the refrigerant circuit 10.

In an embodiment, the fluid can be diverted from a location via which atwo-phase mixture (e.g., gas and liquid) is provided to the fluid inlets40. In such an embodiment, the two-phase mixture can reduce an amount ofheat generated by the porous gas bearing 30. In an embodiment, reducingan amount of heat can, for example, reduce the likelihood of bearingseizure caused by thermal growth of the shaft 42. In an embodiment, thetwo-phase mixture can also increase a viscosity of the working fluid forthe porous gas bearing 30, thereby increasing a loading capacity of theporous gas bearing 30.

In an embodiment, a consideration for the fluid flow F is to provide asuitable pressure to form a fluid layer 54 between the shaft 42 and theporous surface layer 36. It will be appreciated that a pressure of thefluid flow F is relatively more important than a flow rate of the fluidflow. In an embodiment, the pressure of the fluid flow F can be based ona discharge pressure of the compressor (e.g., compressor 12 in FIG. 1).A particular pressure may be selected based on a size (e.g., a weight)of a rotor and impeller assembly of the compressor 12. A minimumpressure can be determined based on when the rotor and impeller assemblylift (e.g., are spaced) from the porous gas bearing 30. It will beappreciated that the pressure of the fluid flow F can depend on arefrigerant type and compressor operating range. Examples of pressureranges for representative refrigerants can include, but are not limitedto, at or about 2 bar to at or about 24 bar for R-134a; at or about 4bar to at or about 55 bar for R-410A; at or about 1 bar to at or about20 bar for R-1234ze; at or about 2 bar to at or about 24 bar for R-513A;and at or about 0.5 bar to at or about 3.5 bar for R-1233zd.

Referring again to FIG. 2C, the damper chambers 48 can also be providedwith an aperture 56. The aperture 56 can include an orifice 58 that isselectively sized to enable fluid F to escape from the damper chamber48. This can, for example, prevent over-pressurization of the damperchamber 48. It will be appreciated that the aperture 56 and orifice 58are optional and may not be included in the housing 34. If included, theorifice 58 would be fluidly connected to the fluid source 52 so thatfluid leaving the orifice is returned to the fluid source 52.

FIGS. 3A and 3B show a porous gas bearing 60 with a damping system,according to an embodiment. FIG. 3A is an axial cross-section of theporous gas bearing 60 along the longitudinal axis L-L of the shaft 42.FIG. 3B is a radial cross-section of the porous gas bearing 60. Unlessspecific reference is made, FIGS. 3A and 3B will be described generally.

Features of the porous gas bearing 60 may be the same as or similar tofeatures of the porous gas bearing 30 (FIGS. 2A, 2B). Such features arelabeled with like reference numbers and are generally not described inadditional detail.

In the illustrated embodiment, the damping system includes a biasingmember 64 disposed in a passageway 62. In an embodiment, the biasingmember 64 can be a spring 64. In an embodiment, the spring 64 caninclude a wave spring 64. In an embodiment, the spring 64 can beinstalled in the porous gas bearing 60 under tension. The pre-loadingtension of the spring 64 can be selected to control an amount of dampingprovided by the spring 64 when the porous gas bearing 60 is in use.

The porous gas bearing 60 with the damping system includes the housing34. In the illustrated embodiment, the housing 34 can include a firstsegment 34A and a second segment 34B. The first segment 34A may bedisposed radially outward (with respect to the shaft 42) of the secondsegment 34B. The damping system (e.g., the biasing member 64) isdisposed between the first segment 34A and the second segment 34B of thehousing 34.

As shown in FIG. 3B, in an embodiment, the first segment 34A of thehousing 34 can include a retainer 66. In an embodiment, the retainer 66can be a notch 66. An end section of the biasing member 64 can beinserted into the retainer 66. The arrangement of the biasing member 64in the retainer 66 can, for example, prevent the biasing member 64 frommoving (e.g., spinning, etc.) about the longitudinal axis L-L. It willbe appreciated that the retainer 66 may be optional. In an embodiment,if the retainer 66 is not present, the spring may move within thehousing 34. However, because the biasing member 64 can be pre-loaded,the movement within the housing 34 may be minimal.

In operation, the shaft 42 rotates about the longitudinal axis L-L. Theshaft 42 is subject to deflection in the radial direction R. To reducean amount of movement in the radial direction R, the biasing member 64of the damping system can absorb force (e.g., be compressed) from thedisplacement of the shaft 42 in the radial direction R.

A plurality of O-rings 68 are disposed at ends of the housing 34 tofluidly seal the passageway 62. In an embodiment, the O-rings 68 canprovide damping if the biasing member 64 is compressed. In anembodiment, the O-rings 68 can also account for slight misalignmentbetween bearings disposed at different locations of the shaft 42.

According to an embodiment, the damping system of the porous gas bearing60 and the damping system of the porous gas bearing 30 can be combinedin a single embodiment to include the dampers 38 and the biasing member64.

FIGS. 4A and 4B show a porous gas bearing 80 with a damping system,according to an embodiment. FIG. 4A is an axial cross-section of theporous gas bearing 80 along the longitudinal axis L-L of the shaft 42.FIG. 4B is a radial cross-section of the porous gas bearing 80. Unlessspecific reference is made, FIGS. 4A and 4B will be described generally.

Features of the porous gas bearing 80 may be the same as or similar tofeatures of the porous gas bearing 30 (FIGS. 2A, 2B, 2C) and thefeatures of the porous gas bearing 60 (FIGS. 3A, 3B).

In the illustrated embodiment, the damping system includes a pluralityof biasing members 84. In an embodiment, the plurality of biasingmembers 84 can include a plurality of O-rings 84. In an embodiment, theplurality of O-rings 84 can include two O-rings 84. It will beappreciated that a number of the biasing members 84 can vary dependingon a desired amount of damping to be provided by the damping system.

The porous gas bearing 80 having the damping system includes the housing34. In the illustrated embodiment, the housing 34 includes the firstsegment 34A and the second segment 34B. The first segment 34A may bedisposed radially outward (with respect to the shaft 42) of the secondsegment 34B. The damping system (e.g., the biasing member 84) isdisposed between the first segment 34A and the second segment 34B of thehousing 34.

As shown in FIG. 4A, the second segment 34B of the housing 34 caninclude a plurality of retainers 86 (e.g., notches 86). The plurality ofretainers 86 can provide a fixed location at which the biasing members84 can be disposed and to prevent the biasing members 84 from being ableto move axially (e.g., in a direction that is parallel to thelongitudinal axis L-L). In an embodiment, the biasing members 84 can bemade of a material that is compatible with refrigerant and lubricantsfor refrigerant. Examples of suitable materials include, but are notlimited to, epichlorohydrin, nitrile, neoprene, viton, and the like.

According to an embodiment, the damping system of the porous gas bearing80 and the damping systems of one or more of the porous gas bearings 30and 60 can be combined in a single embodiment to include the dampers 38,the biasing member 64, and the biasing members 84.

FIGS. 5A-5D show a porous gas bearing 100 with a damping system,according to an embodiment. FIG. 5A is an axial cross-section of theporous gas bearing 100 along the longitudinal axis L-L of the shaft 42.FIG. 5B is a radial cross-section of the porous gas bearing 100. FIG. 5Cis an axial cross-section of the porous gas bearing 100 and the dampingsystem of FIG. 5D along the longitudinal axis L-L of the shaft 42. FIG.5D is a radial cross-section of the porous gas bearing 100 having amodified damping system. Unless specific reference is made, FIGS. 5A and5B will be described generally and FIGS. 5C and 5D will be describedgenerally.

Features of the porous gas bearing 100 may be the same as or similar tofeatures of the porous gas bearing 30 (FIGS. 2A, 2B), the features ofthe porous gas bearing 60 (FIGS. 3A, 3B), and the features of the porousgas bearing 80 (FIGS. 4A, 4B).

With reference to FIGS. 5A and 5B, the illustrated damping systemincludes a plurality of damping structures 104A. The damping structures104A may alternatively be referred to as the squeeze film 104A. In theillustrated damping system, the damping structures 104A are hermeticallysealed damping structures 104A. Four damping structures 104A areillustrated. It will be appreciated that a number of the dampingstructures 104A can vary.

The damping structure 104A has a housing 106A with a fluid 108A filledwithin the housing 106A. The housing 106A is flexible. A flexibility ofthe housing 106A as well as the properties of the fluid 108A within thehousing 106A can determine a stiffness of the damping structure 104A.The stiffness of the damping structure 104A can determine an amount ofdamping possible by the damping system in FIGS. 5A and 5B. The stiffnessand damping may on multiple factors such as, but not limited to, bearingsize, bearing clearance, or the like. In an embodiment, the dampingstructure 104A may have a stiffness coefficient from at or about from10⁶ MN/m to at or about 10⁸ MN/m and a damping coefficient from at orabout 10 N*s/m to at or about 6×10⁵ N*s/m, depending on the bearingclearance and size.

With reference to FIGS. 5C and 5D, the illustrated damping systemincludes a plurality of damping structures 104B. The damping structures104B may alternatively be referred to as the squeeze film 104B. In theillustrated damping system, the damping structures 104B are nothermetically sealed damping structures 104B. Four damping structures104B are illustrated. It will be appreciated that a number of thedamping structures 104B can vary.

The damping structure 104B has a housing 106B with a fluid 108B filledwithin the housing 106B. Different from the damping structure 104A inFIGS. 5A and 5B, the damping structure 104B includes a fluid inlet 110and orifice 112. Fluid 108B is provided to the housing 106B. In anembodiment, the fluid 108B may be the same as the fluid F that isprovided to the porous gas surface 36. In such an embodiment, the fluid108B can be refrigerant. It will be appreciated that fluid inlet 110allows fluid to move both into the orifice 112 and out of the orifice112.

The housing 106B is flexible. A flexibility of the housing 106B as wellas the properties of the fluid 108B, amount of the fluid 108B, andpressure of the fluid 108B within the housing 106B can determine astiffness of the damping structure 104B. The stiffness of the dampingstructure 104B can determine an amount of damping possible by thedamping system in FIGS. 5C and 5D. The damping structure 104B may have avariable stiffness based on the feeding of the fluid 108B into thehousing 106B.

According to an embodiment, the damping systems of the porous gasbearing 100 in FIGS. 5A-5D and the damping systems of the porous gasbearings 30, 60, and 80 can be combined in a single embodiment toinclude the dampers 38, the biasing member 64, the biasing members 84,and the damping structures 104A or 104B.

FIGS. 6A and 6B show a porous gas bearing 120 with a damping system,according to an embodiment. FIG. 6A is an axial cross-section of theporous gas bearing 120 along the longitudinal axis L-L of the shaft 42.FIG. 6B is a radial cross-section of the porous gas bearing 120. Theporous gas bearing 120 and damping system are substantially the same asthe porous gas bearing 60 and the damping system 62 in FIGS. 3A, 3B.Unless specific reference is made, FIGS. 6A and 6B will be describedgenerally.

In the illustrated embodiment, the porous surface layer 36 includes aplurality of grooves 124. The grooves 124 can be formed radially aboutthe porous gas bearing 120. The grooves 124 extend axially within theporous gas bearing 120. The grooves 124 can prevent a swirling of thefluid.

FIG. 7 is a schematic view of a porous gas bearing 140 having a dampingsystem, according to an embodiment. FIG. 7 is an axial cross-section ofthe porous gas bearing 140, according to an embodiment.

The porous gas bearing 140 in FIG. 7 can be utilized in a compressor(e.g., compressor 12 in FIG. 1) of a refrigerant circuit (e.g.,refrigerant circuit 10 in FIG. 1) of an HVACR system.

The porous gas bearing 140 is substantially the same as the porous gasbearing 30 in FIGS. 2A, 2B. In the porous gas bearing 140, the dampingsystem includes a combination of the damping systems in FIGS. 2A-5D. Inthe porous gas bearing 140, the dampers 38 are included along with anadditional damper 142. The additional damper 142 can be selected fromthe damping systems that are described in FIGS. 3A-5D. Accordingly, thedamper 142 can include one or more of the spring 64, the O-ring 84, thedamping structures 104A, or the damping structures 104B. In anembodiment, the grooves 124 (FIGS. 6A, 6B) can be included in the porousgas bearing 140.

FIGS. 8A and 8B are schematic views of a porous gas bearing 160 having adamping system, according to an embodiment. FIG. 8A is an axialcross-section of the porous gas bearing 160 along the longitudinal axisL-L of the shaft 42. FIG. 8B is a radial cross-section of the porous gasbearing 160. Unless specific reference is made, FIGS. 8A and 8B will bedescribed generally.

Features of the porous gas bearing 160 may be the same as or similar tofeatures of the porous gas bearings shows and described in accordancewith FIGS. 2A-7 above. Such features are identified with like referencenumbers.

In the illustrated embodiment, the housing 34 is modified to include aplurality of apertures 162 that fluidly communicate with the passageway164. The apertures 162 extend to the porous surface layer 36 at an anglethat is oriented to provide the fluid F in a direction that is againstthe direction of rotation of the shaft 42. Providing the fluid F at suchan angle can, for example, reduce instability of the shaft 42, andaccordingly, reduce an amount of movement in the radial direction R ofthe shaft.

FIGS. 9A and 9B are schematic views of a porous gas bearing 200 having adamping system, according to an embodiment. FIG. 9A is an axialcross-section of the porous gas bearing 200 along the longitudinal axisL-L of the shaft 42. FIG. 9B is a radial cross-section of the porous gasbearing 200. Unless specific reference is made, FIGS. 9A and 9B will bedescribed generally.

Features of the porous gas bearing 200 may be the same as or similar tofeatures of the porous gas bearings shown and described above inaccordance with FIGS. 2A-7. Such features are labeled with likereference numbers.

In the illustrated embodiment, the damping system includes a damper 202disposed in a passageway 204. In an embodiment, the damper 202 caninclude a wire mesh material. The wire mesh material can be made of ametal or a plastic. The wire mesh material can be knitted to form themesh structure. The knitting of the material can provide a resiliency.The wire mesh material can be included in the passageway 204 so thatmovement of the shaft 42 in the radial direction R can be absorbed. Thedamper 202 can be a relatively cheaper alternative to the dampingstructures 104 (e.g., squeeze film) in the porous gas bearing 200. Amaterial for the wire mesh material of the damper 202 can be selected sothat a particular damping can be provided in the porous gas bearing 200.Suitable materials include, but are not limited to, steel, steel alloys,aluminum, copper, nickel alloys, titanium alloys, nylon, polyethylene,or the like.

According to an embodiment, the damping system of the porous gas bearing200 and the damping system of the porous gas bearings in FIGS. 2A-7 canbe combined in a single embodiment to include the dampers 38, thebiasing member 64, the biasing members 84, and the damper 202.

Aspects

It is to be appreciated that any one of aspects 1-9 can be combined withany one of aspects 10-15, 16-20, 21-29, 30-35, and 36-40. Any one ofaspects 10-15 can be combined with any one of aspects 16-20, 21-29,30-35, and 36-40. Any one of aspects 16-20 can be combined with any oneof aspects 21-29, 30-35, and 36-40. Any one of aspects 21-29 can becombined with any one of aspects 30-35 and 36-40. Any one of aspects30-35 can be combined with any one of aspects 36-40.

Aspect 1. A porous gas bearing, comprising: a housing having a fluidinlet and an aperture; a porous surface layer disposed within thehousing surrounding the aperture in a circumferential direction, theporous surface layer including a plurality of segments arranged in alongitudinal direction of the aperture, the porous surface layer influid communication with the fluid inlet; and a damping system includinga plurality of dampers, the plurality of dampers being disposedcircumferentially about the aperture, wherein the plurality of dampersare arranged in between a first segment of the plurality of segments ofthe porous surface layer and a second segment of the plurality ofsegments of the porous surface layer.

Aspect 2. The porous gas bearing according to aspect 1, wherein thefluid inlet is fluidly connected to a refrigerant circuit.

Aspect 3. The porous gas bearing according to aspect 2, wherein thefluid inlet is fluidly connected to the refrigerant circuit at alocation between a condenser and expansion device of the refrigerantcircuit or at a discharge location of a compressor in the refrigerantcircuit.

Aspect 4. The porous gas bearing according to any one of aspects 1-3,further comprising a plurality of grooves in the porous surface layer.

Aspect 5. The porous gas bearing according to any one of aspects 1-4,wherein the plurality of dampers include a damper inlet and a damperchamber, the damper inlet being disposed at the aperture, and the damperchamber disposed radially outward from the damper inlet.

Aspect 6. The porous gas bearing according to any one of aspects 1-5,wherein the porous surface layer is made of a carbon-graphite material.

Aspect 7. The porous gas bearing according to any one of aspects 1-6,wherein the plurality of dampers include a damper inlet and a damperchamber, the damper inlet being disposed at the aperture, and the damperchamber disposed radially outward from the damper inlet, and the damperchamber is capped.

Aspect 8. The porous gas bearing according to any one of aspects 1-7,wherein the plurality of dampers include a damper inlet and a damperchamber, the damper inlet being disposed at the aperture, and the damperchamber disposed radially outward from the damper inlet, and the damperchamber includes a fluid outlet and an orifice in the fluid outlet, thefluid outlet being disposed radially outward from the aperture relativeto the damper chamber.

Aspect 9. The porous gas bearing according to any one of aspects 1-8,the damper system further comprising one or more of a spring, an O-ring,a squeeze film, and a wire mesh.

Aspect 10. A refrigerant circuit, comprising: a compressor, a condenser,an expansion device, and an evaporator fluidly connected, wherein thecompressor includes a shaft, the shaft being supported by a porous gasbearing, the porous gas bearing including: a housing having a fluidinlet and an aperture; a porous surface layer disposed within thehousing surrounding the aperture in a circumferential direction, theporous surface layer including a plurality of segments arranged in alongitudinal direction of the aperture, the porous surface layer influid communication with the fluid inlet; and a damping system includinga plurality of dampers, the plurality of dampers being disposedcircumferentially about the aperture in the housing, wherein theplurality of dampers are arranged in between a first segment of theplurality of segments of the porous surface layer and a second segmentof the plurality of segments of the porous surface layer.

Aspect 11. The refrigerant circuit according to aspect 10, wherein theporous gas bearing is fluidly connected to the refrigerant circuit.

Aspect 12. The refrigerant circuit according to one of aspects 10 or 11,further comprising a fluid source that is fluidly separate from therefrigerant circuit, the fluid source being fluidly connected to theporous gas bearing.

Aspect 13. The refrigerant circuit according to any one of aspects10-12, wherein the damper system further comprises one or more of aspring, an O-ring, a squeeze film, and a wire mesh.

Aspect 14. The refrigerant circuit according to any one of aspects10-13, wherein the porous gas bearing is fluidly connected to therefrigerant circuit at a location configured to receive a mixed gas andliquid fluid from the refrigerant circuit.

Aspect 15. The refrigerant circuit according to any one of aspects10-14, wherein the refrigerant circuit is a lubricant free refrigerantcircuit.

Aspect 16. A centrifugal compressor, comprising: a shaft that rotates;and a porous gas bearing, the porous gas bearing including: a housinghaving a fluid inlet and an aperture; a porous surface layer disposedwithin the housing surrounding the aperture in a circumferentialdirection, the porous surface layer including a plurality of segmentsarranged in a longitudinal direction of the aperture, the porous surfacelayer in fluid communication with the fluid inlet; and a damping systemincluding a plurality of dampers, the plurality of dampers beingdisposed circumferentially about the aperture in the housing, whereinthe plurality of dampers are arranged in between a first segment of theplurality of segments of the porous surface layer and a second segmentof the plurality of segments of the porous surface layer.

Aspect 17. The centrifugal compressor according to aspect 16, whereinthe damper system further comprises one or more of a spring, an O-ring,a squeeze film, and a wire mesh.

Aspect 18. The centrifugal compressor according to one of aspects 16 or17, wherein the shaft is configured to rotate from at or about 10,000revolutions per minute to at or about 150,000 revolutions per minute.

Aspect 19. The centrifugal compressor according to any one of aspects16-18, wherein the porous gas bearing is a radial bearing that supportsthe shaft.

Aspect 20. The centrifugal compressor according to any one of aspects16-19, wherein the plurality of dampers include a damper inlet and adamper chamber, the damper inlet being disposed at the aperture, and thedamper chamber disposed radially outward from the damper inlet.

Aspect 21. A porous gas bearing, comprising: a housing having a fluidinlet and an aperture; a porous surface layer disposed within thehousing surrounding the aperture in a circumferential direction, theporous surface layer in fluid communication with the fluid inlet; and adamping system including a biasing member, the biasing member beingdisposed in a passageway that extends along the longitudinal directionof the aperture and circumferentially about the aperture, wherein thebiasing member is arranged radially outward from the porous surfacelayer.

Aspect 22. The porous gas bearing according to aspect 21, wherein thefluid inlet is fluidly connected to a refrigerant circuit.

Aspect 23. The porous gas bearing according to aspect 22, wherein thefluid inlet is fluidly connected to the refrigerant circuit at alocation between a condenser and expansion device of the refrigerantcircuit or at a discharge location of a compressor in the refrigerantcircuit.

Aspect 24. The porous gas bearing according to any one of aspects 21-23,further comprising a plurality of grooves in the porous surface layer.

Aspect 25. The porous gas bearing according to any one of aspects 21-24,wherein the biasing member includes a spring.

Aspect 26. The porous gas bearing according to any one of aspects 21-25,wherein the porous surface layer is made of a carbon-graphite material.

Aspect 27. The porous gas bearing according to any one of aspects 21-26,wherein the biasing member includes a wave spring.

Aspect 28. The porous gas bearing according to any one of aspects 21-27,further comprising a plurality of dampers, the plurality of dampersbeing disposed circumferentially about the aperture in the housing.

Aspect 29. The porous gas bearing according to any one of aspects 21-28,the damper system further comprising one or more of an O-ring, a squeezefilm, and a wire mesh.

Aspect 30. A refrigerant circuit, comprising: a compressor, a condenser,an expansion device, and an evaporator fluidly connected, wherein thecompressor includes a shaft, the shaft being supported by a porous gasbearing, the porous gas bearing including: a housing having a fluidinlet and an aperture; a porous surface layer disposed within thehousing surrounding the aperture in a circumferential direction, theporous surface layer in fluid communication with the fluid inlet; and adamping system including a biasing member, the biasing member beingdisposed in a passageway that extends along the longitudinal directionof the aperture and circumferentially about the aperture, wherein thebiasing member is arranged radially outward from the porous surfacelayer.

Aspect 31. The refrigerant circuit according to aspect 30, wherein theporous gas bearing is fluidly connected to the refrigerant circuit.

Aspect 32. The refrigerant circuit according to one of aspects 30 or 31,further comprising a fluid source that is fluidly separate from therefrigerant circuit, the fluid source being fluidly connected to theporous gas bearing.

Aspect 33. The refrigerant circuit according to any one of aspects30-32, wherein the damper system further comprises one or more of anO-ring, a squeeze film, and a wire mesh.

Aspect 34. The refrigerant circuit according to any one of aspects30-33, wherein the porous gas bearing is fluidly connected to therefrigerant circuit at a location configured to receive a mixed gas andliquid fluid from the refrigerant circuit.

Aspect 35. The refrigerant circuit according to any one of aspects30-34, wherein the refrigerant circuit is a lubricant free refrigerantcircuit.

Aspect 36. A centrifugal compressor, comprising: a shaft that rotates;and a porous gas bearing, the porous gas bearing including: a housinghaving a fluid inlet and an aperture; a porous surface layer disposedwithin the housing surrounding the aperture in a circumferentialdirection, the porous surface layer in fluid communication with thefluid inlet; and a damping system including a biasing member, thebiasing member being disposed in a passageway that extends along thelongitudinal direction of the aperture and circumferentially about theaperture, wherein the biasing member is arranged radially outward fromthe porous surface layer.

Aspect 37. The centrifugal compressor according to aspect 36, whereinthe damper system further comprises one or more of an O-ring, a squeezefilm, and a wire mesh.

Aspect 38. The centrifugal compressor according to one of aspects 36 or37, wherein the shaft is configured to rotate from at or about 10,000revolutions per minute to at or about 150,000 revolutions per minute.

Aspect 39. The centrifugal compressor according to any one of aspects36-38, wherein the porous gas bearing is a radial bearing that supportsthe shaft.

Aspect 40. The centrifugal compressor according to any one of aspects36-39, wherein the biasing member is pre-tensioned to provide a selectedamount of damping.

The terminology used in this specification is intended to describeparticular embodiments and is not intended to be limiting. The terms“a,” “an,” and “the” include plural forms as well, unless clearlyindicated otherwise. The terms “comprises” and/or “comprising,” whenused, indicated the presence of the stated features, integers, steps,operations, elements, and/or components, but do not preclude thepresence or addition of one or more other features, integers, steps,operations, elements, and/or components.

With regard to the preceding description, it is to be understood thatchanges may be made in detail, especially in matters of the constructionmaterials employed and the shape, size, and arrangement of parts,without departing from the scope of the present disclosure. The word“embodiment” may, but does not necessarily, refer to the sameembodiment. The embodiments and disclosure are examples only. Other andfurther embodiments may be devised without departing from the basicscope thereof, with the true scope and spirit of the disclosure beingindicated by the claims that follow.

What is claimed is:
 1. A porous gas bearing, comprising: a housinghaving a fluid inlet and an aperture; a porous surface layer disposedwithin the housing surrounding the aperture in a circumferentialdirection, the porous surface layer in fluid communication with thefluid inlet; and a damping system including a biasing member, thebiasing member being disposed in a passageway that extends along thelongitudinal direction of the aperture and circumferentially about theaperture, wherein the biasing member is arranged radially outward fromthe porous surface layer.
 2. The porous gas bearing according to claim1, wherein the fluid inlet is fluidly connected to a refrigerantcircuit.
 3. The porous gas bearing according to claim 2, wherein thefluid inlet is fluidly connected to the refrigerant circuit at alocation between a condenser and expansion device of the refrigerantcircuit or at a discharge location of a compressor in the refrigerantcircuit.
 4. The porous gas bearing according to claim 1, furthercomprising a plurality of grooves in the porous surface layer.
 5. Theporous gas bearing according to claim 1, wherein the biasing memberincludes a spring.
 6. The porous gas bearing according to claim 1,wherein the porous surface layer is made of a carbon-graphite material.7. The porous gas bearing according to claim 1, wherein the biasingmember includes a wave spring.
 8. The porous gas bearing according toclaim 1, further comprising a plurality of dampers, the plurality ofdampers being disposed circumferentially about the aperture in thehousing.
 9. The porous gas bearing according to claim 1, the dampersystem further comprising one or more of an O-ring, a squeeze film, anda wire mesh.
 10. A refrigerant circuit, comprising: a compressor, acondenser, an expansion device, and an evaporator fluidly connected,wherein the compressor includes a shaft, the shaft being supported by aporous gas bearing, the porous gas bearing including: a housing having afluid inlet and an aperture; a porous surface layer disposed within thehousing surrounding the aperture in a circumferential direction, theporous surface layer in fluid communication with the fluid inlet; and adamping system including a biasing member, the biasing member beingdisposed in a passageway that extends along the longitudinal directionof the aperture and circumferentially about the aperture, wherein thebiasing member is arranged radially outward from the porous surfacelayer.
 11. The refrigerant circuit according to claim 10, wherein theporous gas bearing is fluidly connected to the refrigerant circuit. 12.The refrigerant circuit according to claim 10, further comprising afluid source that is fluidly separate from the refrigerant circuit, thefluid source being fluidly connected to the porous gas bearing.
 13. Therefrigerant circuit according to claim 10, wherein the damper systemfurther comprises one or more of an O-ring, a squeeze film, and a wiremesh.
 14. The refrigerant circuit according to claim 10, wherein theporous gas bearing is fluidly connected to the refrigerant circuit at alocation configured to receive a mixed gas and liquid fluid from therefrigerant circuit.
 15. The refrigerant circuit according to claim 10,wherein the refrigerant circuit is a lubricant free refrigerant circuit.16. A centrifugal compressor, comprising: a shaft that rotates; and aporous gas bearing, the porous gas bearing including: a housing having afluid inlet and an aperture; a porous surface layer disposed within thehousing surrounding the aperture in a circumferential direction, theporous surface layer in fluid communication with the fluid inlet; and adamping system including a biasing member, the biasing member beingdisposed in a passageway that extends along the longitudinal directionof the aperture and circumferentially about the aperture, wherein thebiasing member is arranged radially outward from the porous surfacelayer.
 17. The centrifugal compressor according to claim 16, wherein thedamper system further comprises one or more of an O-ring, a squeezefilm, and a wire mesh.
 18. The centrifugal compressor according to claim16, wherein the shaft is configured to rotate from at or about 10,000revolutions per minute to at or about 150,000 revolutions per minute.19. The centrifugal compressor according to claim 16, wherein the porousgas bearing is a radial bearing that supports the shaft.
 20. Thecentrifugal compressor according to claim 16, wherein the biasing memberis pre-tensioned to provide a selected amount of damping.